New Playroom?

My SO and I are purchasing a house soon and would like to convert one of the bedrooms into our chins bedroom/playroom. Do you guys have any advice or ideas on how to set this up? Is there anything in particular I should know about setting up a full room? Any information would be appreciated from safety tips to what you guys like to have out during playtime!
Also, what do you think about shelves on the walls? Safe or not?